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- =pod
- =head1 NAME
- BIO_s_file, BIO_new_file, BIO_new_fp, BIO_set_fp, BIO_get_fp,
- BIO_read_filename, BIO_write_filename, BIO_append_filename,
- BIO_rw_filename - FILE bio
- =head1 SYNOPSIS
- #include <openssl/bio.h>
- BIO_METHOD * BIO_s_file(void);
- BIO *BIO_new_file(const char *filename, const char *mode);
- BIO *BIO_new_fp(FILE *stream, int flags);
- BIO_set_fp(BIO *b,FILE *fp, int flags);
- BIO_get_fp(BIO *b,FILE **fpp);
- int BIO_read_filename(BIO *b, char *name)
- int BIO_write_filename(BIO *b, char *name)
- int BIO_append_filename(BIO *b, char *name)
- int BIO_rw_filename(BIO *b, char *name)
- =head1 DESCRIPTION
- BIO_s_file() returns the BIO file method. As its name implies it
- is a wrapper round the stdio FILE structure and it is a
- source/sink BIO.
- Calls to BIO_read() and BIO_write() read and write data to the
- underlying stream. BIO_gets() and BIO_puts() are supported on file BIOs.
- BIO_flush() on a file BIO calls the fflush() function on the wrapped
- stream.
- BIO_reset() attempts to change the file pointer to the start of file
- using fseek(stream, 0, 0).
- BIO_seek() sets the file pointer to position B<ofs> from start of file
- using fseek(stream, ofs, 0).
- BIO_eof() calls feof().
- Setting the BIO_CLOSE flag calls fclose() on the stream when the BIO
- is freed.
- BIO_new_file() creates a new file BIO with mode B<mode> the meaning
- of B<mode> is the same as the stdio function fopen(). The BIO_CLOSE
- flag is set on the returned BIO.
- BIO_new_fp() creates a file BIO wrapping B<stream>. Flags can be:
- BIO_CLOSE, BIO_NOCLOSE (the close flag) BIO_FP_TEXT (sets the underlying
- stream to text mode, default is binary: this only has any effect under
- Win32).
- BIO_set_fp() set the fp of a file BIO to B<fp>. B<flags> has the same
- meaning as in BIO_new_fp(), it is a macro.
- BIO_get_fp() retrieves the fp of a file BIO, it is a macro.
- BIO_seek() is a macro that sets the position pointer to B<offset> bytes
- from the start of file.
- BIO_tell() returns the value of the position pointer.
- BIO_read_filename(), BIO_write_filename(), BIO_append_filename() and
- BIO_rw_filename() set the file BIO B<b> to use file B<name> for
- reading, writing, append or read write respectively.
- =head1 NOTES
- When wrapping stdout, stdin or stderr the underlying stream should not
- normally be closed so the BIO_NOCLOSE flag should be set.
- Because the file BIO calls the underlying stdio functions any quirks
- in stdio behaviour will be mirrored by the corresponding BIO.
- On Windows BIO_new_files reserves for the filename argument to be
- UTF-8 encoded. In other words if you have to make it work in multi-
- lingual environment, encode file names in UTF-8.
- =head1 EXAMPLES
- File BIO "hello world":
- BIO *bio_out;
- bio_out = BIO_new_fp(stdout, BIO_NOCLOSE);
- BIO_printf(bio_out, "Hello World\n");
- Alternative technique:
- BIO *bio_out;
- bio_out = BIO_new(BIO_s_file());
- if(bio_out == NULL) /* Error ... */
- if(!BIO_set_fp(bio_out, stdout, BIO_NOCLOSE)) /* Error ... */
- BIO_printf(bio_out, "Hello World\n");
- Write to a file:
- BIO *out;
- out = BIO_new_file("filename.txt", "w");
- if(!out) /* Error occurred */
- BIO_printf(out, "Hello World\n");
- BIO_free(out);
- Alternative technique:
- BIO *out;
- out = BIO_new(BIO_s_file());
- if(out == NULL) /* Error ... */
- if(!BIO_write_filename(out, "filename.txt")) /* Error ... */
- BIO_printf(out, "Hello World\n");
- BIO_free(out);
- =head1 RETURN VALUES
- BIO_s_file() returns the file BIO method.
- BIO_new_file() and BIO_new_fp() return a file BIO or NULL if an error
- occurred.
- BIO_set_fp() and BIO_get_fp() return 1 for success or 0 for failure
- (although the current implementation never return 0).
- BIO_seek() returns the same value as the underlying fseek() function:
- 0 for success or -1 for failure.
- BIO_tell() returns the current file position.
- BIO_read_filename(), BIO_write_filename(), BIO_append_filename() and
- BIO_rw_filename() return 1 for success or 0 for failure.
- =head1 BUGS
- BIO_reset() and BIO_seek() are implemented using fseek() on the underlying
- stream. The return value for fseek() is 0 for success or -1 if an error
- occurred this differs from other types of BIO which will typically return
- 1 for success and a non positive value if an error occurred.
- =head1 SEE ALSO
- L<BIO_seek(3)|BIO_seek(3)>, L<BIO_tell(3)|BIO_tell(3)>,
- L<BIO_reset(3)|BIO_reset(3)>, L<BIO_flush(3)|BIO_flush(3)>,
- L<BIO_read(3)|BIO_read(3)>,
- L<BIO_write(3)|BIO_write(3)>, L<BIO_puts(3)|BIO_puts(3)>,
- L<BIO_gets(3)|BIO_gets(3)>, L<BIO_printf(3)|BIO_printf(3)>,
- L<BIO_set_close(3)|BIO_set_close(3)>, L<BIO_get_close(3)|BIO_get_close(3)>
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